As you move from left to right across a period, what generally happens to the atomic radius?

As you move from left to right across a period in the periodic table, the atomic radius generally decreases. This phenomenon can be attributed to the increasing positive charge of the nucleus as additional protons are added to the nucleus with each successive element. As the nuclear charge increases, the electrons are drawn closer to the nucleus, resulting in a smaller atomic radius. The increase in nuclear charge outweighs the effects of increased electron-electron repulsion among the electrons, which would tend to expand the atomic size.

In summary, the combination of increased nuclear charge with relatively stable electron shielding leads to a net contraction of the atomic radius across a period, making the chosen answer correct.